fix(Segmentation): Support only one frame

[jlopes90]

Fix: https://github.com/cornerstonejs/cornerstone3D/issues/1059#issuecomment-2155718355

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[pieper]

Thanks for investigating this and providing the PR with a link to the cornerstone issue. While that link is helpful, please make your contribution here self-contained and describe in your commit message, and in code comments as needed, specifically, please clarify:

• what the issue is you are trying to fix
• what the behavior is without this change
• what the behavior is after this change
• why this change fixes the issue
• why you don't think this will have any side-effects for other code in the future

It would also be great to have a unit test that illustrates this. That is, a test that demonstrates a valid use-case that fails without this change but works with the change.

Also, see the guidelines for commit messages and correct your commit as indicated: https://github.com/dcmjs-org/dcmjs?tab=readme-ov-file#for-maintainers-and-contributors

I don't mean to be super-picky here, but this repo is used by a lot of people and subtle bugs can occur if we aren't careful. I want to be sure someone who sees your contribution in the future fully understands it.

[jlopes90]

generateSegmentation supports two or more frames and does not support just one frame and gives an error.

When testing just one frame for example:

Cornerstone3D.Segmentation.generateSegmentation([cacheImage], labelmapData, metaData);

and shows the results of errors.

First Error

let distance1 = distanceDatasetPairs[1][0];

So I created a new variable, distance1 is zero, for just one frame. But if NumberOfFrames was two or more get this distanceDatasetPairs[1][0].

// If the frame is one, it is zero
let distance1 = 0;

if (ds.NumberOfFrames > 1) {
    distance1 = distanceDatasetPairs[1][0];
}

Second Error

if (ds.NumberOfFrames === 1)
    ds.PerFrameFunctionalGroupsSequence = [
        ds.PerFrameFunctionalGroupsSequence
    ];

I removed this code and it works similar to two or more frames. But I don't know what it does, I have little knowledge of segmentation in dicom.

The result:

[jlopes90]

There is another way without using this pull request or change.

How does just one frame work:

Cornerstone3D.Segmentation.generateSegmentation(
    [cacheImage, cacheImage],
    labelmapData,
    metaData
);

[cacheImage, cacheImage] both "cacheImage" are the same, just ignore it and it works only one frame.